/**
  * {@inheritdoc}
  */
 public function addUniqueField($field)
 {
     $pluginInfo = $this->pluginList->getNext($this->subjectType, 'addUniqueField');
     if (!$pluginInfo) {
         return parent::addUniqueField($field);
     } else {
         return $this->___callPlugins('addUniqueField', func_get_args(), $pluginInfo);
     }
 }